The BMW X3 is a Crossover SUV marketed by the German automaker BMW since 2003 as a Sports Activity Vehicle. Based on the BMW 3 Series platform, and now in its second generation. For its first generation, BMW designed the X3 in conjunction with Magna Steyr of Graz, Austriawho manufactured all X3s under contract to BMW. Production of the second generation vehicle transferred to BMW's Spartanburg plant in South Carolina, United States. BMW presented the xActivity concept vehicle at the Detroit Auto Show in 2003 based on the 3 Series platform and featuring a vestigial roof without windows. The X3 itself premiered in late 2003 using an automatic four-wheel drive system marketed as xDrive and sharing its rear suspension with the E46 330xi. Based on the E46 BMW 3 Series platform and drivetrain, the X3 3.